No, but my guess is we’re still a while away, based on what we’ve seen in Beta so far.
The animations for this new round of heroes aren’t finished yet, which seems like a bit of an indicator that there’s some development time left.
We also will likely see a second round of testing of the first group of Season 3 Heroes before release.
There may also be some testing of Season 3 content — so far all we’ve seen are the Heroes.
Beta just reopened a couple hours ago, and the new Season 3 Heroes are all that’s in this current testing cycle.
It’s typical that each testing cycle has one content focus, at least until a release is imminent, so we’ll likely see other new content come to Beta in the coming weeks.